JP2013210066A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission having sprockets with changeable effective diameters and a chain wrapped around the sprockets wherein the vibration of the chain is suppressed and the strength of the sprockets is well secured.SOLUTION: When the effective diameters of first and second sprockets are changed, a plurality of first and second segments 310, 320 are radially moved along a first guide part 301 or a second guide part 302 of a base member 300 to be generally positioned on a same circumference, and a chain support member 321 of the second segment 320 is disposed on the axial side of a primary shaft 30p or the like of the first segment 310 so that the overlapped amount thereof with the first segment 310 in the circumferential direction is more increased as the effective diameters of the first and second sprockets are more decreased.

Description

  The present invention relates to an automatic transmission including a sprocket capable of changing an effective diameter and a chain wound around the sprocket.

  Conventionally, as this type of transmission, a transmission having a variable diameter sprocket capable of changing an effective diameter by moving a plurality of small diameter sprockets each meshable with a chain is known (for example, Patent Document 1). reference). Also, this type of transmission has a variable sprocket that can change the effective diameter by moving a plurality of meshing segments that can mesh with the chain in the radial direction so as to be positioned on the same circumference. Is known (see, for example, Patent Document 2). In this transmission, guide segments are arranged between meshing segments adjacent to each other in the circumferential direction, and the guide segments are moved in the radial direction so as to be positioned on substantially the same circumference as the meshing segments and wound around a plurality of meshing segments. A chain or the like to be supported is supported from the inner peripheral side by a guide segment, and thereby, the winding portion of the chain is made close to a perfect circle.

US Patent 3,914,410 Specification International Publication No. 02/0888575

  In the transmission described in Patent Document 1, since the effective diameter of the variable-diameter sprocket is changed by moving a plurality of small-diameter sprockets, it is difficult to bring the chain winding portion close to a perfect circle. There is a possibility that vibration of the chain may occur due to the winding portion having a polygonal shape. On the other hand, in the transmission described in Patent Document 2, the winding portion of the chain or the like can be made close to a perfect circle shape by the plurality of guide segments, so that the occurrence of vibration of the chain or the like can be suppressed. However, if guide segments are arranged between meshing segments adjacent to each other in the circumferential direction, the total number of teeth that mesh with a chain or the like in the variable sprocket to transmit power decreases, and the strength of the variable sprocket may be reduced.

  SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to suppress the vibration of the chain and ensure the strength of the sprocket in an automatic transmission including a sprocket whose effective diameter can be changed and a chain wound around the sprocket. And

  The automatic transmission according to the present invention employs the following means in order to achieve the main object.

An automatic transmission according to the present invention includes:
A first sprocket capable of changing the effective diameter and attached to the drive side rotating shaft, a second sprocket capable of changing the effective diameter and attached to the driven side rotating shaft, and the first and second sprockets are wound around An automatic transmission comprising a chain to be changed and a speed change drive mechanism for changing an effective diameter of the first and second sprockets,
The first and second sprockets are
A base member having a plurality of radial first guide portions and a plurality of radial second guide portions alternately arranged with the first guide portions;
A plurality of first segments that can be engaged with the chain and movable in a radial direction along a side surface of the first guide portion;
A plurality of second segments capable of supporting the chain from the inner peripheral side and movable in a radial direction along a side surface of the second guide portion;
The speed change drive mechanism changes the effective diameter of the first and second sprockets by moving the first and second segments in a radial direction so as to be located on the same circumference,
The second segment is disposed laterally in the axial direction of the first segment so that the amount of overlap with the first segment in the circumferential direction increases as the effective diameter of the first and second sprockets decreases. It is characterized by that.

  The first and second sprockets constituting the automatic transmission include a plurality of radial first guide portions, a base member alternately disposed with the first guide portions and having a plurality of radial second guide portions. A plurality of first segments which can be engaged with the chain and movable in the radial direction of the base member along the side surface of the first guide portion; and the side surface of the second guide portion which can support the chain from the inner peripheral side And a plurality of second segments movable in the radial direction of the base member. Further, the speed change drive mechanism effectively moves the first and second sprockets by moving the first and second segments radially along the side surface of the first or second guide portion so as to be positioned on the same circumference. The diameter is changed, thereby changing the gear ratio between the driving side rotating shaft and the driven side rotating shaft. The second segment is arranged on the side of the first segment in the axial direction so that the amount of overlap with the first segment in the circumferential direction increases as the effective diameters of the first and second sprockets decrease.

  As a result, when the effective diameter of the first sprocket or the second sprocket is minimized, the plurality of first segments are assembled so as to substantially constitute one sprocket, and the chain support member of the second segment Can be assembled in a ring shape on the side of the plurality of first segments. Further, when the effective diameters of the first and second sprockets are increased, a gap is formed between the first segments adjacent to each other. In this automatic transmission, the gap is filled. Since the second segment can be moved, the chain can be supported from the inner peripheral side by each second segment. Therefore, in this automatic transmission, the chain is supported from the inner peripheral side by the plurality of second segments so that the winding portion of the chain approaches a perfect circle shape, and the second segment is disposed between the first segments adjacent to each other in the circumferential direction. Compared with the case where the segments are arranged, the total number of teeth that mesh with the chains in the first and second sprockets and transmit power can be increased. As a result, the vibration of the chain can be suppressed and the strength of the first and second sprockets can be ensured satisfactorily.

  The second segment may include a chain support member capable of supporting the chain from the inner peripheral side, and the chain support member may be disposed on both sides of the first segment in the axial direction. As a result, the chain can be more stably supported from the inner peripheral side by the plurality of second segments, so that occurrence of vibration of the chain can be suppressed more favorably.

  Furthermore, the thickness of the chain support member in the axial direction may be smaller than the thickness of the first segment in the axial direction. As a result, the thickness of the first and second sprockets in the axial direction can be reduced, and the entire automatic transmission can be made more compact.

  A plurality of recesses that can be engaged with the chain may be formed on the outer peripheral surface of the chain support member. As a result, the chain can be more stably supported from the inner peripheral side by the plurality of second segments.

  Furthermore, the drive side rotating shaft may be coupled to an output shaft of a prime mover mounted on the vehicle.

It is a schematic block diagram of the power transmission device 20 including the automatic transmission 30 which concerns on one Example of this invention. 1 is a schematic configuration diagram showing a first sprocket 31 included in an automatic transmission 30. FIG. 2 is a schematic configuration diagram showing a first sprocket 31. FIG. FIG. 3 is an enlarged perspective view of a main part showing a first sprocket 31. 2 is a schematic configuration diagram showing a first sprocket 31. FIG. 1 is a schematic configuration diagram of an automatic transmission 30. FIG. (A), (b), and (c) are the schematic diagrams for demonstrating operation | movement of the automatic transmission 30. FIG. It is a schematic block diagram which shows the 1st sprocket 31B which concerns on a modification.

  Next, embodiments of the present invention will be described using examples.

  FIG. 1 is a schematic configuration diagram showing a power transmission device 20 according to an embodiment of the present invention. A power transmission device 20 shown in the figure is mounted on a front wheel drive vehicle and transmits power from an engine (not shown) mounted on the front of the vehicle to left and right front wheels (drive wheels), which are integrally coupled. Transmission case 22 including a converter housing, a transaxle case and a rear cover, a fluid transmission device 24 housed in the transmission case 22, an oil pump 26, a forward / reverse switching mechanism 28, a stepped automatic transmission 30, a gear A mechanism (gear train) 40, a differential mechanism (differential gear) 45, and the like are included. That is, in a vehicle equipped with the power transmission device 20, power from the engine is transmitted to the automatic transmission 30 via the fluid transmission device 24 and the forward / reverse switching mechanism 28, and is shifted in multiple stages by the automatic transmission 30. Then, it is transmitted to the left and right front wheels via the gear mechanism 40 and the differential mechanism 45.

  The fluid transmission device 24 is configured as a fluid torque converter having a lock-up clutch 25, and a pump impeller 24p connected to a crankshaft (output shaft) of an engine (motor) (not shown) via a front cover 23, A turbine runner 24t connected to the input shaft 28i of the forward / reverse switching mechanism 28, a stator 24s that rectifies the flow of hydraulic oil from the turbine runner 24t to the pump impeller 24p, and the like. However, the fluid transmission device 24 may be configured as a fluid coupling that does not include the stator 24s.

  The oil pump 26 is configured as a gear pump including a pump assembly including a pump body and a pump cover, an external gear connected to the pump impeller 24p, and the like. The oil pump 26 is driven by power from the engine, sucks hydraulic oil (ATF) stored in an oil pan (not shown), and pumps it to a hydraulic control device (not shown).

  The forward / reverse switching mechanism 28 includes a double-pinion planetary gear mechanism and a hydraulic brake and clutch that are operated by hydraulic pressure from a hydraulic control device (not shown). By engaging or releasing the brake and clutch of the forward / reverse switching mechanism 28, the rotation direction of the input element (sun gear) of the planetary gear mechanism constituting the forward / reverse switching mechanism 28 and the output element (carrier) of the planetary gear mechanism The rotational direction of the input element can be matched or reversed, or the transmission of power from the input element to the output element can be cut off.

  The automatic transmission 30 includes a primary shaft 30p as a driving side rotating shaft connected to an output element of the planetary gear mechanism of the forward / reverse switching mechanism 28, and a secondary shaft as a driven side rotating shaft extending in parallel with the primary shaft 30p. 30s, the first sprocket 31 that can change the effective diameter (pitch circle diameter) and is attached to the primary shaft 30p, the second sprocket 32 that can change the effective diameter and is attached to the secondary shaft 30s, and the first And a chain (for example, an endless roller chain) 33 wound around the second sprockets 31 and 32 and a speed change drive mechanism 34 for changing the effective diameters of the first and second sprockets 31 and 32.

  The gear mechanism 40 includes a counter drive gear 41 fixed to one end of the secondary shaft 30 s, and a counter driven gear 43 fixed to one end of a counter shaft 42 extending in parallel with the secondary shaft 30 s and meshing with the counter drive gear 41. And a drive pinion gear (final drive gear) 44 fixed to the other end of the counter shaft 42.

  The differential mechanism 45 includes a differential ring gear (final driven gear) 46 that meshes with the drive pinion gear 44 of the gear mechanism 40, a differential case that supports the differential ring gear, and a pair of pinion mates fixed to a shaft that is rotatably supported by the differential case. A gear (bevel gear) and a pair of side gears (not shown) that mesh with each pinion mate gear are included. The left and right differential shafts 47 a and 47 b are fixed to the side gears of the differential mechanism 45.

  2 and 3 are schematic configuration diagrams showing the first sprocket 31 included in the automatic transmission 30. FIG. Here, since the first sprocket 31 and the second sprocket 32 of the embodiment basically have the same configuration, the first sprocket 31 will be mainly described below.

  As shown in FIGS. 2 and 3, the first sprocket 31 includes two base members 300 formed in an annular shape, and a plurality of first sprockets 31 that are disposed between the two base members 300 and can mesh with the chain 33. It includes a first segment 310 (six in the embodiment) and a plurality (six in the embodiment) of second segments 320 arranged between the two base members 300. A primary shaft 30p as a drive side rotation shaft is fixed at the center of the two base members 300, and the chain 33 basically meshes with the first segment 310 between the two base members 300. Note that a secondary shaft 30s as a driven-side rotation shaft is fixed to the center of the two base members 300 of the second sprocket 32. As shown in FIG. 2, each base member 300 includes a plurality of first guide portions 301 extending radially and a plurality of second guide portions arranged alternately with the first guide portions 301 and extending radially. 302.

  The first guide portion 301 is formed as a substantially rectangular elongated hole or recess (groove) extending radially from the central portion of the base member 300 toward the outer periphery, and is equally spaced (60 ° interval in the embodiment). A plurality (six in the embodiment) are formed. A plurality of engaging recesses 303 are formed on both sides of each first guide portion 301 at a predetermined interval (equal interval in the embodiment) in the extending direction of the first guide portion 301. The second guide portion 302 is a substantially rectangular slot or recess (groove) extending in the radial direction from the center portion of the base member 300 toward the outer periphery between the first guide portions 301 adjacent to each other (center). A plurality (6 in the embodiment) are formed at equal intervals (60 ° in the embodiment). A plurality of engaging recesses 304 are formed on both sides of each second guide portion 302 at a predetermined interval (equal interval in the embodiment) in the extending direction of the second guide portion 302. As shown in FIG. 2, the engagement recesses 303 and 304 adjacent in the circumferential direction of the base member 300 are positioned on substantially the same circumference, and the engagement recesses 303 and 304 in the radial direction of the base member 300 are located. The number 304 is determined according to the number of gears that can be set by the automatic transmission 30.

  The first segment 310 corresponds to a segment obtained by equally dividing a relatively small-diameter sprocket into a plurality of parts (6 in the embodiment), and as shown in FIGS. It has a plurality of teeth 311 that can mesh with the (roller). In addition, a guide projection 313 that engages with the first guide portion 301 of the base member 300 extends outward from the center portion in the circumferential direction of the side surfaces on both sides of the first segment 310. Further, the first segment 310 has a first lock mechanism 315 for locking (fixing the position) the first segment 310 to the base member 300.

  As shown in FIG. 5, the first lock mechanism 315 is formed in a guide projection 313 on one side (upper side in FIG. 5) of the first segment 310 and extends in parallel with the primary shaft 30p (or the secondary shaft 30s). A guide pin 316 slidably disposed therein, a base end rotatably supported by the first segment 310, and a first guide portion 301 formed on one (upper side in FIG. 5) base member 300. A first stopper 317 having two free ends engageable with the engaging recesses 303 on both sides, a base end rotatably supported by the first segment 310, and the other (lower side in FIG. 5) base member A second stopper 318 having two free ends engageable with engaging recesses 303 on both sides of the first guide portion 301 formed in 300, and free ends of the first and second stoppers 317 and 318 And a spring 319 for urging the base member 300. As shown in the drawing, the distal end of the guide pin 316 protrudes from the outer surface of the one base member 300, and the distal end of the guide pin 316 is formed on the free end side slightly from the proximal end of the first stopper 317. Abuts the contact surface. A pressing portion 317a extends from the proximal end of the first stopper 317 toward the second stopper 318, and from the proximal end of the second stopper 318, the distal end of the pressing portion 317a of the first stopper 317 and The pressed portion 318a that contacts is extended to the opposite side to the two free ends.

  According to the first lock mechanism 315 configured as described above, the two free ends of the first stopper 317 and the two free ends of the second stopper 318 are biased by the spring 319 so as to be separated from each other. Therefore, as shown in FIG. 5, in the state where each free end of the first stopper 317 and the engaging recess 303 are engaged and each free end of the second stopper 318 and the engaging recess 303 are engaged, the spring The first segment 310 can be well locked (position fixed) with respect to the base member 300 while maintaining good engagement between the first and second stoppers 317 and 318 and the engagement recess 303 by the urging force of 319. Can do.

  On the other hand, when the guide pin 316 is pressed from the outside of the base member 300 (upward in FIG. 5) and moves into the hole (downward in FIG. 5), it is pressed by the end of the guide pin 316. The first stopper 317 rotates so that each free end is separated from the corresponding base member 300. Further, as the first stopper 317 is rotated, the pressed portion 318a of the second stopper 318 is pressed by the pressing portion 317a of the first stopper 317, whereby each free end of the second stopper 318 corresponds. It rotates so as to be separated from the base member 300. Therefore, according to the first lock mechanism 315, the first and second stoppers 317 and 318 are engaged with the engagement recess 303 by pressing the guide pin 316 from the outside of the base member 300 (upward in FIG. 5). That is, the lock of the first segment 310 with respect to the base member 300 can be released.

  As shown in FIGS. 2 to 5, the second segment 320 includes two chain support members 321 and a connecting member 322 (see FIG. 5) that connects the two chain support members 321. The chain support member 321 equally divides the annular plate body having a thickness smaller than the thickness (width) of the first segment 310 (teeth 311) in the axial direction of the primary shaft 30p or the like into six equal parts (in the embodiment, six equal parts). Correspond to the substantially arc-shaped segments obtained in this way, each having a circumferential outer peripheral surface. As shown in FIG. 3, one chain support member 321 is arranged on each side of the first segment 310 in the axial direction of the primary shaft 30p or the secondary shaft 30s. Further, notches 324 for avoiding interference with the guide projections 313 of the first segment 310 are formed at both ends of each chain support member 321 in the longitudinal direction. Furthermore, guide protrusions 323 that engage with the second guide portions 302 of the base member 300 are extended outward from both ends of the connecting member 322 that connects the two chain support members 321. In addition, the notch part 314 for avoiding interference with the connection member 322 and the guide protrusion 323 of the 2nd segment 320 is formed in the both ends of the 1st segment 310 (refer FIG. 1).

  The second segment 320 also has a second lock mechanism 325 for locking (fixing the position) the second segment 320 to the base member 300. As shown in FIG. 5, the second lock mechanism 325 is formed in a guide protrusion 323 on one side (upper side in FIG. 5) of the connecting member 322 and extends in parallel with the primary shaft 30p (or the secondary shaft 30s). The guide pin 326 is slidably disposed on the base member 300, the base end is rotatably supported by the connecting member 322, and both sides of the second guide portion 302 formed on the base member 300 on one side (upper side in FIG. 5). The first stopper 327 having two free ends that can be engaged with the engaging recess 304, the base end that is rotatably supported by the connecting member 322, and the base member 300 on the other side (lower side in FIG. 5). The second stopper 328 having two free ends engageable with the engaging recesses 304 on both sides of the second guide portion 302 formed, and the free ends of the first and second stoppers 327 and 328 are used as the base member 300. And a spring 329 for urging. As shown in the drawing, the distal end of the guide pin 326 protrudes from the outer surface of the one base member 300, and the distal end of the guide pin 326 is formed on the free end side slightly from the proximal end of the first stopper 327. Abuts the contact surface. A pressing portion 327a extends from the proximal end of the first stopper 327 toward the second stopper 328, and from the proximal end of the second stopper 328, the distal end of the pressing portion 327a of the first stopper 327 and A pressed portion 328a that abuts extends to the opposite side of the two free ends.

  According to the second lock mechanism 325 configured as described above, the spring 329 biases the two free ends of the first stopper 327 and the two free ends of the second stopper 328 so as to be separated from each other. Accordingly, as shown in FIG. 5, in the state where the free ends of the first stopper 327 and the engaging recess 304 are engaged and the free ends of the second stopper 328 and the engaging recess 304 are engaged, the spring The engagement between the first and second stoppers 327 and 328 and the engagement recess 304 is favorably maintained by the biasing force of 329, and the connecting member 322, that is, the second segment 320 is well locked (position) with respect to the base member 300. Fixed).

  In contrast, when the guide pin 326 is pressed from the outside of the base member 300 (upward in FIG. 5) and moves into the hole (downward in FIG. 5), it is pressed by the end of the guide pin 326. The first stopper 327 rotates so that each free end is separated from the corresponding base member 300. Further, as the first stopper 327 rotates, the pressed portion 328a of the second stopper 328 is pressed by the pressing portion 327a of the first stopper 327, whereby each free end of the second stopper 328 corresponds. It rotates so as to be separated from the base member 300. Therefore, according to the second lock mechanism 325, the first and second stoppers 327 and 328 are engaged with the engagement recess 304 by pressing the guide pin 326 from the outside of the base member 300 (upward in FIG. 5). That is, the lock of the second segment 320 with respect to the base member 300 can be released.

  In the first and second sprockets 31 and 32 configured as described above, the first and second stoppers 317 and 318 of the first lock mechanism 315 and the first and second stoppers 327 and 328 of the second lock mechanism 325 are used. Are engaged with the engagement recesses 303 and 304 located on the innermost peripheral side of the base member 300, the plurality of first segments 310 are substantially continuously connected to one sprocket on the same circumference. The chain support members 321 of the plurality of second segments 320 are configured to form a plurality of second segments 320 on substantially the same circumference as the plurality of first segments 310 and substantially one ring on both sides of the plurality of first segments 310. They are assembled to form a body (see the left half in FIG. 2).

  Further, the first and second stoppers 317 and 318 of the first lock mechanism 315 and the first and second stoppers 327 and 328 of the second lock mechanism 325 are engaged with the engagement recesses 303 and 304 on the outer peripheral side of the base member 300. As they are combined, the plurality of first and second segments 310 and 320 move outward in the radial direction of the base member 300 so as to be positioned on substantially the same circumference, and accordingly the first sprocket 31 and the second sprocket 31 are moved. The effective diameter of the sprocket 32, that is, the pitch circle diameter defined by the plurality of first sprockets 31 increases. The first and second stoppers 317 and 318 of the first lock mechanism 315 and the first and second stoppers 327 and 328 of the second lock mechanism 325 are engaged with the engagement recesses 303 and 304 on the inner peripheral side of the base member 300. As the engagement proceeds, the plurality of first and second segments 310 and 320 move radially inward of the base member 300 so as to be positioned on substantially the same circumference, and accordingly, the first sprocket 31 and the second sprocket 31 The effective diameter (pitch circle diameter) of the two sprockets 32 decreases.

  As shown in FIG. 6, the speed change drive mechanism 34 includes the one base member 300 of the first sprocket 31 and the second sprocket 32, that is, the guide pins 316 and 326 of the first and second lock mechanisms 315 and 325. A segment moving member 35 disposed on the side of the base member 300, and an actuator 36 for reciprocating the segment moving member 35 in a direction orthogonal to both the primary shaft 30p and the secondary shaft 30s. In the embodiment, the segment moving member 35 includes a first guide recess 351 that guides the guide pins 316 and 326 that protrude from the base member 300 so as to face the one base member 300 of the first sprocket 31, and the second sprocket 32. And a second guide recess 352 for guiding the guide pins 316 and 326 protruding from the base member 300 so as to face the one base member 300.

  The first guide recess 351 is open at both corners at the end of the segment moving member 35 on the primary shaft 30p side (left side in FIG. 6), and has two guide surfaces 353 and 355 facing each other. As shown in the figure, the guide surface 353 and the guide surface 355 are spaced from each other at a central portion in the width direction of the first guide recess 351 (the direction perpendicular to the moving direction of the segment moving member 35) from one opening. It is formed so as to narrow toward the narrowest portion 357 and to expand from the narrowest portion 357 toward the other opening. The minimum distance between the guide surface 353 and the guide surface 355 (the distance at the narrowest portion 357) is determined to be slightly larger than the outer diameters of the guide pins 316 and 326. Further, the depth of the first guide recess 351 is kept engaged with the guide pins 316 and 326 from the opening on the upstream side in the rotation direction of the first sprocket 31 (upper left in FIG. 6) toward the narrowest portion 357. It is determined so as to become shallower and relatively steeply to the extent, and to become deeper and steeper from the narrowest portion 357 toward the opening on the downstream side in the rotation direction of the first sprocket 31 (lower right in FIG. 6).

  The second guide recess 352 is open at both corners at the end of the segment moving member 35 on the secondary shaft 30s side (right side in FIG. 6), and has two guide surfaces 354 and 356 facing each other. As shown in the figure, the guide surface 354 and the guide surface 356 are narrower as the distance between them decreases from one opening toward the narrowest portion 358 defined at the center in the width direction of the second guide recess 352. It is formed so as to expand from the portion 358 toward the other opening. The minimum distance between the guide surface 354 and the guide surface 356 (the distance at the narrowest portion 358) is determined to be slightly larger than the outer diameters of the guide pins 316 and 326. Further, the depth of the second guide recess 352 is kept engaged with the guide pins 316 and 326 from the opening on the upstream side in the rotation direction of the second sprocket 32 (lower right in FIG. 6) toward the narrowest portion 358. It is determined so that it becomes relatively steep and shallow to a certain extent, and becomes steep and deeper from the narrowest portion 358 toward the opening on the downstream side in the rotation direction of the second sprocket 32 (upper right in FIG. 6).

  In the embodiment, the actuator 36 is coupled to the motor 361, the ball screw 362 connected to the rotation shaft of the motor 361, the segment moving member 35, and moves forward and backward in the axial direction of the ball screw 362 as the motor 361 rotates. The linear actuator includes a slider 363 and the like. However, as the actuator 36, a hydraulic actuator or an electromagnetic actuator configured to reciprocate the segment moving member 35 in a direction orthogonal to both the primary shaft 30p and the secondary shaft 30s may be used.

  According to the speed change drive mechanism 34 configured in this way, the first and second lock mechanisms 315 and 315 are passed each time the narrowest portions 357 and 358 of the first and second guide recesses 351 and 352 of the segment moving member 35 are passed. The guide pins 316 and 326 of 325 are once pressed into the corresponding base member 300 and quickly returned. As a result, the first and second stoppers 317 and 318 of the first lock mechanism 315 and the first and second stoppers 327 and 328 of the second lock mechanism 325 are engaged with the engagement recesses 303 and 304 of the base member 300. If the segment moving member 35 is moved to the primary shaft 30p or the secondary shaft 30s side by a predetermined amount by the actuator 36, the first and second stoppers 317, 318, 327, 328 and the engaging recesses 303, 304 are The first and second segments 310 and 320 are moved in the radial direction of the base member 300 via the guide pins 316 and 326 while the first and second stoppers 317, 318, 327, and 328 are moved. Engage with engaging recesses 303 and 304 on the outer peripheral side or the inner peripheral side rather than those engaged so far. Door can be. Therefore, the effective diameter of the first and second sprockets 31 and 32 is changed by reciprocating the segment moving member 35 by the actuator 36, and the gear ratio between the primary shaft 30p and the secondary shaft 30s is changed stepwise. It becomes possible to do.

  In the embodiment, when the lowest gear position (first speed) of the automatic transmission 30 is formed, the first and second stoppers 317, 318, 327, and 328 of the first sprocket 31 are, for example, the highest of the base member 300. While engaging with the engaging recesses 303 and 304 formed on the inner peripheral side, the segment moving member 35 is located closest to the primary shaft 30p as shown by the solid line in FIG. The narrowest portion 357 of 351 is located on the circumference defined by the guide pins 316 and 326 of the first sprocket 31. Further, when the minimum gear position of the automatic transmission 30 is formed, the first and second stoppers 317, 318, 327, and 328 of the second sprocket 32 are formed on the outermost peripheral side of the base member 300, for example. The narrowest portion 358 of the second guide recess 352 of the segment moving member 35 is positioned on the circumference defined by the guide pins 316 and 326 of the second sprocket 32 while engaging with the combined recesses 303 and 304.

  Further, when the maximum gear position of the automatic transmission 30 is formed, the first and second stoppers 317, 318, 327, and 328 of the first sprocket 31 are formed on the outermost peripheral side of the base member 300, for example. The segment moving member 35 is positioned closest to the secondary shaft 30 s as shown by a two-dot chain line in FIG. 6, and the narrowest portion 357 of the first guide concave portion 351 of the segment moving member 35 is engaged. Is located on the circumference defined by the guide pins 316 and 326 of the first sprocket 31. When the maximum gear position of the automatic transmission 30 is formed, the first and second stoppers 317, 318, 327, and 328 of the second sprocket 32 are formed on the innermost side of the base member 300, for example. The narrowest portion 358 of the second guide concave portion 352 of the segment moving member 35 is positioned on the circumference defined by the guide pins 316 and 326 of the second sprocket 32 while engaging with the engaging concave portions 303 and 304.

  Next, the operation of the automatic transmission 30 will be described.

  As described above, when changing the gear stage of the automatic transmission 30, that is, the gear ratio between the primary shaft 30p and the secondary shaft 30s, the actuator 36 is used to move the segment moving member 35 between the primary shaft 30p and the secondary shaft 30s. It is moved by a predetermined amount in a direction orthogonal to. That is, when the shift stage is upshifted, the actuator 36 moves the segment moving member 35 by a predetermined amount from the primary shaft 30p side to the secondary shaft 30s side. Accordingly, as shown in FIGS. 7A to 7C, the radial direction of the base member 300 is set such that the first and second segments 310 and 320 of the first sprocket 31 are located on substantially the same circumference. While moving outward, the first and second segments 310 and 320 of the second sprocket 32 move radially inward of the base member 300 so that they are positioned on substantially the same circumference.

  When the gear stage is upshifted in this way, the effective diameter (pitch circle diameter) of the first sprocket 31 increases stepwise, and a gap is formed between the first segments 310 adjacent to each other. In the automatic transmission 30, as shown in FIGS. 7A to 7C, the second segment 320 (chain support member 321) can be moved so as to fill the gap. Further, when the shift stage is upshifted, the effective diameter of the second sprocket 32 is gradually reduced, and the gap between the adjacent first segments 310 is gradually reduced. At this time, the chain support members 321 of the second segments 320 of the second sprocket 32 are adjacent to each other as the effective diameter of the second sprocket 32 decreases, as shown in FIGS. 7 (a) to 7 (c). When the maximum shift speed is formed when the base member 300 moves inward in the radial direction so that the amount of overlap with the first segment 310 in the circumferential direction increases, an annular shape is formed at the side of the plurality of first segments 310. To gather.

  Further, when the shift stage is downshifted, the actuator 36 moves the segment moving member 35 by a predetermined amount from the secondary shaft 30s side to the primary shaft 30p side. As a result, the first and second segments 310 and 320 of the first sprocket 31 move radially inward of the base member 300 so as to be positioned on substantially the same circumference, while the first and second segments of the second sprocket 32 are moved. The two segments 310 and 320 move outward in the radial direction of the base member 300 so that the two segments 310 and 320 are located on substantially the same circumference.

  When the gear position is downshifted in this way, the effective diameter of the first sprocket 31 is gradually reduced, and the gap between the adjacent first segments 310 is gradually reduced. At this time, the chain support member 321 of each second segment 320 of the first sprocket 31 has a base so that the overlapping amount in the circumferential direction with the adjacent first segments 310 increases as the effective diameter of the first sprocket 31 decreases. When the member 300 moves inward in the radial direction and the lowest gear position is formed, the members 300 gather in an annular shape on the side of the plurality of first segments 310. Further, when the shift stage is downshifted, the effective diameter of the second sprocket 32 increases stepwise, and a gap is formed between the first segments 310 adjacent to each other. In 30, the second segment 320 (chain support member 321) can be moved so as to fill the gap.

  Therefore, in the automatic transmission 30, when changing the gear position, the chain 33 is supported from the inner peripheral side by the chain support members 321 of the plurality of second segments 320, and the winding portion of the chain 33 is brought close to a perfect circle shape. Compared with the case where the second segment 320 is arranged between the first segments 310 adjacent to each other in the circumferential direction, the total number of teeth 311 that mesh with the chain 33 in the first and second sprockets 31 and 32 and transmit power is increased. It becomes possible to make it.

  As described above, the first and second sprockets 31 and 32 constituting the automatic transmission 30 are alternately arranged with the first guide portions 301 and the first guide portions 301 extending radially. The base member 300 having a plurality of second guide portions 302 extending radially and the chain 33 can be engaged with the first guide portion 301 (in the embodiment, the inner side surface 301s of the first guide portion 301). A plurality of first segments 310 that are movable in the radial direction of the base member 300, a chain support member 321 that can support the chain 33 from the inner peripheral side, and a second guide portion 302 (in the embodiment, the second guide portion). A plurality of second segments 320 movable in the radial direction of the base member 300 along the inner side surface 302 s) of the base member 300. Then, the chain support member 321 of the second segment 320 has an increase in the amount of overlap with the first segment 310 in the circumferential direction as the effective diameter of the first and second sprockets 31 and 32 decreases. It arrange | positions in the side in the axial direction of the primary shaft 30p or the secondary shaft 30s.

  As a result, when the effective diameters of the first sprocket 31 and the second sprocket 32 are minimized, the plurality of first segments 310 are assembled so as to substantially constitute one sprocket, and the second segment 320 is assembled. The chain support members 321 can be annularly assembled on the side of the plurality of first segments 310. In addition, when the effective diameters of the first and second sprockets 31 and 32 are increased, a gap is formed between the first segments 310 adjacent to each other. Since the second segment 320 (chain support member 321) can be moved so as to fill in, the chain 33 can be supported from the inner peripheral side by the chain support member 321 of each second segment 320. Therefore, in the automatic transmission 30, the chain 33 is supported from the inner peripheral side by the plurality of second segments 320 to bring the winding portion of the chain 33 close to a perfect circle shape, and the first segments 310 adjacent to each other in the circumferential direction. Compared with the case where the second segment 320 is disposed therebetween, the total number of teeth 311 that mesh with the chain 33 in the first and second sprockets 31 and 32 and transmit power can be increased. As a result, the vibration of the chain 33 can be suppressed, and the strength of the first and second sprockets 31 and 32 can be ensured satisfactorily. Further, the effective diameter of the first and second sprockets 31 and 32 is changed in smaller steps by increasing the total number of teeth 311 that mesh with the chain 33 in the first and second sprockets 31 and 32 and transmit power. be able to.

  Moreover, if the chain support members 321 of the second segment 320 are arranged on both sides in the axial direction of the first segment 310 as in the above embodiment, the plurality of second segments 320 make the chain 33 more stable from the inner peripheral side. Since it can support, generation | occurrence | production of the vibration of the chain 33 can be suppressed more favorably.

  Furthermore, if the thickness of the chain support member 321 in the axial direction of the primary shaft 30p or the like is smaller than the thickness of the first segment 310 in the axial direction (the thickness of the teeth 311) as in the above embodiment, the first and first The thickness (width) in the axial direction of the two sprockets 31 and 32 can be reduced to make the entire automatic transmission 30 more compact.

  In addition, in the said Example, although the chain support member 321 was formed as what has a circumferential-surface-shaped outer peripheral surface, it is not restricted to this. That is, as in the first sprocket 31B according to the modification shown in FIG. 8, a plurality of recesses 321e that can be engaged with the chain 33 are formed on the outer peripheral surface of the chain support member 321B constituting the second segment 320B. Also good. Accordingly, the chain 33 can be supported more stably from the inner peripheral side by the plurality of second segments 320B. In the above embodiment, the transmission drive mechanism 34 has been described as including one segment moving member 35 and an actuator 36. However, the present invention is not limited to this, and the first sprocket 31 and the second sprocket 32 are segmented. The moving member 35 and the actuator 36 may be included.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above embodiment, the effective diameter can be changed and the first sprocket 31 attached to the primary shaft 30p as the driving side rotating shaft, and the effective shaft can be changed and the secondary shaft 30s as the driven side rotating shaft. A second sprocket 32 attached to the first sprocket 31, a chain 33 wound around the first and second sprockets 31, 32, and a speed change drive mechanism 34 for changing the effective diameter of the first and second sprockets 31, 32. The automatic transmission 30 corresponds to an “automatic transmission”, and a plurality of first guide portions 301 extending radially and a plurality of second guides extending radially with the first guide portions 301 being alternately arranged. The base member 300 having the guide portion 302 corresponds to a “base member”, can be engaged with the chain 33, and is a first guide. A plurality of first segments 310 that can move in the radial direction of the base member 300 along 301 correspond to “first segments”, have a chain support member 321 that can support the chain 33 from the inner peripheral side, and a second guide. A plurality of second segments 320 that are movable in the radial direction of the base member 300 along the portion 302 correspond to “second segments”. However, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the invention described in the column of means for solving the problem by the embodiment. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the examples are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is It should be done based on the description.

  As mentioned above, although the embodiment of the present invention has been described using examples, the present invention is not limited to the above-described examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the transmission manufacturing industry.

  20 power transmission device, 22 transmission case, 23 front cover, 24 fluid transmission device, 24p pump impeller, 24s stator, 24t turbine runner, 25 lock-up clutch, 26 oil pump, 28 forward / reverse switching mechanism, 28i input shaft, 30 automatic Transmission, 30p Primary shaft, 30s Secondary shaft, 31, 31B First sprocket, 32 Second sprocket, 33 Chain, 34 Shift drive mechanism, 35 Segment moving member, 36 Actuator, 40 Gear mechanism, 41 Counter drive gear, 42 Counter Shaft, 43 Counter driven gear, 44 Drive pinion gear, 45 Differential mechanism, 46 Diff ring gear, 47a, 47b Differential shaft, 300 Base member, 301 1st gear 302, second guide portion, 303, 304 engaging recess, 310 first segment, 311 teeth, 313 guide protrusion, 314 notch, 315 first lock mechanism, 316, 326 guide pin, 317, 327 first stopper 317a, 327a Pressing portion, 318, 328 Second stopper, 318a, 328a Pressed portion, 319, 329 Spring, 320, 320B Second segment, 321, 321B Chain support member, 321e Concavity, 322 Connecting member, 323 Guide protrusion 324 Notch, 351 First guide recess, 352 Second guide recess, 353, 354, 355, 356 Guide surface, 357, 358 Narrowest part, 361 Motor, 362 Ball screw, 363 Slider.

Claims (5)

A first sprocket capable of changing the effective diameter and attached to the drive side rotating shaft, a second sprocket capable of changing the effective diameter and attached to the driven side rotating shaft, and the first and second sprockets are wound around An automatic transmission comprising a chain to be changed and a speed change drive mechanism for changing an effective diameter of the first and second sprockets,
The first and second sprockets are
A base member having a plurality of radial first guide portions and a plurality of radial second guide portions alternately arranged with the first guide portions;
A plurality of first segments that can be engaged with the chain and movable in a radial direction along a side surface of the first guide portion;
A plurality of second segments capable of supporting the chain from the inner peripheral side and movable in a radial direction along a side surface of the second guide portion;
The speed change drive mechanism changes the effective diameter of the first and second sprockets by moving the first and second segments in a radial direction so as to be located on the same circumference,
The second segment is disposed laterally in the axial direction of the first segment so that the amount of overlap with the first segment in the circumferential direction increases as the effective diameter of the first and second sprockets decreases. An automatic transmission characterized by that. The automatic transmission according to claim 1, wherein
The second segment includes a chain support member capable of supporting the chain from an inner peripheral side, and the chain support member is disposed on both sides in the axial direction of the first segment. Machine. The automatic transmission according to claim 2, wherein
The automatic transmission according to claim 1, wherein a thickness of the chain support member in the axial direction is smaller than a thickness of the first segment in the axial direction. The automatic transmission according to claim 2 or 3,
An automatic transmission characterized in that a plurality of recesses engageable with the chain are formed on an outer peripheral surface of the chain support member. The automatic transmission according to any one of claims 1 to 4,
The automatic transmission is characterized in that the drive-side rotating shaft is connected to an output shaft of a prime mover mounted on a vehicle.